This invention relates to an electrical straight blade plug and connector. More specifically, this invention relates to a straight blade plug and connector having a plug with three box terminals and a cord grip. The box terminals are used to connect the electrical wiring to the plug blades and the cord grip is used to allow the plug to accommodate three different sized cords for versatility. Each box terminal accepts one prong from a single plug and has an assembly screw that can be inserted into a respective box terminal in the same direction as each other screw, facilitating assembly of the plug. The cord grip has a male and female portion and can accommodate three different sized cords by employing and insert that is snap fitted into the female portion, which is rotated and moved up and down depending on the size of the cord such that the cord is held between the insert and the male part of the cord grip. Furthermore, the cord grips have two dovetails on each cord grip for attachment to the plug body that allows the plug to pass UL pull test requirements.
Typically, an electrical cord or conduit is coupled within an electrical connector by a movable conduit jaw. An example of such a jaw is disclosed in Gartland U.S. Pat. No. 3,784,961, the disclosure of which is hereby incorporated herein by reference. Such jaws are able to grip and secure only one general size of conduit. However, generally various sizes of conduits are used for different applications.
The conventional means for accommodating a wide range of conduit diameters has been to use a removable or expendable conduit clamp, i.e., one that is used only when smaller diameter cable is used and removed when larger diameter cable is used. The clamp reduces the opening size of the electrical connector, thereby allowing the conduit clamp to effectively grip the smaller diameter cable within the opening.
Such removable clamps have several disadvantages. The electrical connectors leave the factory with the clamps installed and ready to receive smaller diameter conduit. Thus, if the user forgets to remove the clamp or does not realize removal is necessary and attempts to use larger diameter conduit, the conduit may be damaged. Furthermore, removable clamps are easily lost.
Alternatively, clamps that rotate have been used that allow the clamping mechanism to hold two differently sized conduits. For example, in U.S. Pat. No. 5,562,483 to Hoffman, a clamp can be rotated 90 degrees to hold a large diameter cable in one position and a small diameter cable in a second position. However, this device is limited in only two positions for two different sized cables.
Additionally, typically electrical plugs and connectors each have three box terminals, one each for the hot, neutral and ground prongs with each box terminal having a screw that secures the electrical wire therein. In conventional plugs and connectors, the screws are inserted from various directions, thereby requiring the orientation of the plug or connector to be altered during assembly.
Furthermore, many conventional cord grips are merely coupled to the plug or connector housing using conventional means, such as screws. Typically these methods can be inadequate and fail if the wires connected to the plug or connector are pulled. In many cases the cord grip is not secure enough to pass the UL pull test requirements.
Thus, a need exists to provide an improved electrical wiring device with a clamp capable of gripping various sizes of electrical conduit, is easy to assemble and can withstand the UL pull test requirements.
Accordingly, it is an object of the present invention is to provide an electrical connector having a cord grip that can vary the diameter of cable received therein.
Another object of the present invention to provide an electrical connector having a cord grip that can receive at least three different diameter cables.
Still another object of the present invention is to provide an electrical connector that has three box terminals, each having a screw that inserts therein in the same direction as each other screw, facilitating assembly.
Yet another object of the present invention is to provide an electrical connector having a cord grip that couples to the housing using at least one dove tail type protrusion and groove connection to securely attach the cord grip the housing.
These objects are basically obtained by an electrical connector, comprising a housing having a front face with first and second openings therein, the first and second openings receiving first and second electrical prongs, respectively, first and second box terminals are coupled to the housing using first and second fastening members, the first fastening member being inserted into the housing from substantially the same direction as the second fastening member, first and second electrical contacts at least partially received in the first and second box terminals, respectively, and adapted to couple to the first and second electrical prongs, respectively, and a cord grip coupled to the housing and having an insert, the insert capable of being adjusted to at least two different positions and thereby allowing electrical cords of differing diameters to be frictionally held by the cord grip.
Other objects, advantages, and salient features of the present invention will become apparent to those skilled in the art from the following detailed description, which, when taken in conjunction with the annexed drawings, discloses a preferred embodiment of the invention.